In a liquid crystal panel used in a liquid crystal display device or some other device, a polarizing film is usually laminated onto each of both sides of a liquid crystal cell, which is composed of a liquid crystal layer arranged between a pair of transparent substrates, to interpose a pressure-sensitive-adhesive layer between the cell and the polarizing film. Such a pressure-sensitive-adhesive layer is required to have a high endurance. For example, in an endurance test under heating and humidifying conditions, which is usually made as an environment accelerating test, the polarizing film is required not to undergo the generation of a peel or a lift, or other defects caused by the pressure-sensitive-adhesive layer.
Such pressure-sensitive-adhesive compositions for optical use have been variously investigated. Suggested is, for example, a pressure-sensitive-adhesive composition about which even when an optical film is bonded to the composition and subsequently the resultant is put into high-temperature and high-humidity conditions, the optical film is not peeled or formed (see, for example, Patent Document 1).